Combining SADIe and AxsJAX To Improve Accessibility Darren Lunn, Simon Harper and Sean Bechhofer
Combining SADIe and AxsJAX To Improve Accessibility
Dec 08, 2014
The advent of Web 2.0 technologies has allowed once static Web documents to be transformed into online interactive applications. To facilitate the accessibility of this dynamic content, Google have developed the AxsJAX framework that can insert Accessible Rich Internet Applications (ARIA) statements into the content dynamically. Such statements allow assistive technologies to interact with dynamic content and make it accessible to users. SADIe is an approach that uses semantic annotations of a Website's Cascading Style Sheet (CSS) to drive a transformation process that can improve access to Web pages for visually impaired users who use a screen reader. Previously SADIe transcoded static pages by refactoring the content into a format more suited to the sequential audio output of a screen reader. In this paper we present a prototype SADIe transcoder that uses CSS annotations to generate AxsJAX framework code and insert it into Web pages. Such an approach allows users to access static content using a consistent set of key presses in a manner akin to an online application. This demonstrates the flexibility of the SADIe approach as the same annotations can be used to generate an alternative transcoding format. It also supports the use of SADIe as a lightweight method for allowing Web designers to make use of AxsJAX without requiring knowledge of the underlying AxsJAX technologies.
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Combining SADIe and AxsJAX To Improve Accessibility
Darren Lunn, Simon Harper and Sean Bechhofer
Summary• SADIe transcodes content based upon the
meaning of the visual rendering.
• AxsJAX allows ARIA statements to be injected into Web content dynamically.
• Can combine SADIe’s identification of elements and AxsJAX functionality to create consistent page interaction.
2
The Web• Focus on presenting information visually
– Images– Columns– Chunks
• Some knowledge is only available implicitly from the page rendering.
3
Implicit Information
4
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Main Content
Assistive Technologies• Traversal of content is serial.
• Important information may not be encountered until later on.
• Some information such as menus can be repeated for every page.
5
Transcoding• Adaptation of content from one format to
another.
• Rules / Patterns.– Can adapt a large number of pages.– Can suffer from reduced accuracy.
• Annotation.– Accurate.– Time consuming as every page is annotated.
6
SADIe Approach• The visual rendering of a Web element
informs the user of its purpose.
• The CSS defines the visual rendering.
• Identifying the purpose of the CSS definition implicitly defines the purpose of the Web element.
• A single CSS definition is applied to every page within the Website.
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SADIe Transcoding
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Heading Summary
Main Story
Heading
Summary
Main Story
The Web 2.0• Content can change dynamically without
page refreshes.
• Documents are no longer static but interactive.– YouTube– Flickr– Facebook
• Akin to an application.9
ARIA• Accessible Rich Internet Applications.
• Allows developers to mark-up dynamic and interactive regions of content
• Mark-up provides assistive technology with access to dynamic content.
10
Google AxsJAX• Open source framework to insert ARIA into
documents dynamically.
• Collection of JavaScripts that contain all the necessary code for inserting ARIA.
• Uses high level abstract patterns
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Content Navigation Rules• A key part of the framework.
• Uses XML and XPath expressions to define where ARIA should be inserted.
• Assigns key presses to ARIA statements to allow users to interact with content.
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Using CSS To Define XPaths• Xpath can use absolute locations.
– /html/body/table[3]/tbody/
• XPath can also use element properties to match nodes.– //ul[@class=‘X’]
• CSS employs element attributes to apply rendering.– <ul id="cnnNavigation">
13
Use SADIe To Create CNR• Use CSS annotations to identify areas of
content.
• Use annotations to generate the XPath and AxsJAX Code.
• Rather than rearrange the document, inject AxsJAX into document dynamically.
14
Consistent Key Presses• N: move to next chunk of information.
• P: move to previous chunk of information.
• M: jump to menu.
• S: provide a summary of the page
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SADIe + AxsJAX
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Pressing S reads out the summary but does not
loose the focus of the story
Pressing S reads out the summary but does not
loose the focus of the story
Future Work• More key presses
– Chose four key presses applicable to a majority of pages
• User studies– Demonstrated the technical feasibility of the
approach
• Dynamic content– So far focused on consistent navigation of static
pages17
Summary• SADIe transcodes content based upon the
meaning of the visual rendering.
• AxsJAX allows ARIA statements to be injected into Web content dynamically.
• Can combine SADIe’s identification of elements and AxsJAX functionality to create consistent page interaction.
18
Questions?
http://hcw.cs.manchester.ac.uk/
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